1. Field of the Invention
This invention relates to a means for allowing a floor or roof to "float" in response to random loading (caused by increased live load), adverse environmental loading or earthquake motion loading that might otherwise cause cracks in the vertical wall covering which is applied to the vertical studs beneath the floor or roof system.
2. Background of the Invention
Prior to the present invention, vertical metal studs in the frame of a building were connected directly to metallic horizontal joists or top tracks that support and are affixed to the floor or roof. This meant that the vertical studs and horizontal joists for floors or roofs were rigidly secured to each other in a manner that allowed little, if any, vertical displacement of the floor or roof. The fixed relationship of nonload bearing or non-bearing studs and floors or roofs systems presented serious problems for heavy office floors, or in those parts of the country that receive heavy snow fall, as illustrations. In the case of the floors and the roofs a heavy load of snow causes a downward pressure on the vertical nonbearing studs. But because the horizontal members were rigidly secured to the vertical studs, there was not way to alleviate the downward pressure. The result was that the vertical pressure would cause unsightly and costly cracks in the wall coverings and generally weaken the wall beneath the structure. When the snow melted. the cracks in the walls would become larger as the walls expanded in response to the lessening vertical pressure from the snow-burdened joists.
In addition, in areas where there are exceedingly hot days such as in the desert and metal framing studs are used, roofs have a tendency to expand. With such expansion the roofs have no flexibility and upward movement will also cause the wall coverings to crack.
In the case of office and other types of building occupancies, it is commonly known that the floor system is differentially loaded at different times during the day or night. This loading is caused primarily by people and/or equipment. An example would be the office floor system that is loaded by people during work hours, at which time a larger downward pressure is being exerted on the non-bearing walls below. During the times in which the floor does not support extra loading, the floor system moves upward away from the non-bearing walls.
The present invention overcomes such problems of inflexibility that plagued the prior art building systems by providing horizontal roof, or floor joists that move vertically relative to the vertical studs. By allowing the top tracks to flex when the roof is subject to environmental pressure, the vertical forces on the roof top tracks are harmlessly released. In that manner, the vertical stresses caused by the environmental pressures and live loads or earthquake motion induce loading are never transmitted to the walls, thereby preventing the wall covering cracks that were a chronic problem in prior art structures.